1. Technical Field
The following relates generally to power saving for integrated circuits, and more specifically to a method and apparatus for low-level input sense amplification.
2. Background
A sense amplifier is an element in read circuitry for computer memory that makes up circuitry on an Integrated Circuit (IC) memory chip. Specifically, the sense amplifier is part of the read circuitry that is used during data read operations when data is read from the memory chip. One main function of the sense amplifier is for reading logic levels from a bit line that represents a data bit stored in a memory cell in the IC memory chip. In doing so, the sense amplifier may amplify small voltage swings to recognizable logic levels so data represented by them can be translated accurately at an output terminal of the IC memory chip.
Typically, one sense amplifier is used for each column of memory cells, which may lead to hundreds or thousands of identical sense amplifiers on a single IC memory chip. As such, improvement in sense amplifier design may be magnified by many multiples because of the large number of sense amplifiers used in each IC memory chip. One issue that may be addressed by an improved sense amplifier design is read disturbance effect for programmable memory devices that utilize fuses, where a bit value may be written to the programmable memory device by blowing a fuse to signify whether the bit value should be a logical one or zero. The read disturb effect is an unintentional programming phenomena that affects un-blown fuses during frequent read operations. Specifically, as a current through an un-blown fuse increases, the fuse resistance may also increase due to Electrical Migration (EM).
For example, the fuse resistance for an un-blown fuse, which usually amounts to tens of ohms during one read operation, can rise to a significantly higher level, such as tens of thousands of ohms after multiple, sequential read operations. This increase in resistance may ultimately result in the fuse being read incorrectly as a blown fuse, which is meant to represent a high resistance-value device. Thus, although no programming operation has been intentionally performed on an un-blown fuse, the un-blown fuse may be still be read as a blown fuse after a certain number of repeated read operations on the blow fuse because the resistance detected for the un-blown fuse will have increased to a level as high as that expected of a blown fuse. Avoiding or minimizing such read disturb effects is another constraint for e-fuse sense amplifier design.
Although numerous approaches have been taken to address these issues, existing solutions typically require additional complexities in the design and manufacturing of sense amplifiers. Thus, it would be desirable to be able to improve the efficiency of sense amplifiers while minimizing costs.
In accordance with common practice, some of the drawings may be simplified for clarity. Thus, the drawings may not depict all of the elements of a given apparatus (e.g., device) or method. Finally, like reference numerals may be used to denote like features throughout the specification and figures.